Chapter 18.4, Problem 21SC

Explanation of Solution

Justification:

• “No”, one can define ordinary method for finding average of elements of array.
• For example, if the class “BankAccount” implements the class “Measurable”, an array “BankAccount[]”is convertible to a “Measurable[]” array.
• Here, the return type used for the method is “double”, and there is no need for using generic types.

Implementing generic method “average”:

//define a method average with type double

public static double average(

Measurable[] objects)

{

//if the length of objects is zero

if (objects.length == 0)

{

//return zero

return 0;

}

//declare a variable to hold sum

double sum = 0;

//iterate through the objects

for (Measurable obj : objects)

{

//find the sum of elements

sum = sum + obj...